Creamy Hungarian Bean Soup

I haven't tried this recipe yet, it looked like it might be interesting.

2 c White Beans
2 small Onions, chopped
1 Leek, rinsed and chopped
3 Carrots, diced
6 Garlic Cloves, minced
1 tsp Salt
1/4 tsp Black Pepper
1 Tbsp Sweet Hungarian Paprika
6 Tbsp Flour
1/2 c Sour Cream
2 tsp Cider Vinegar

Soak beans overnight. Drain them and place in large soup pot with onions, leek, carrots, and garlic. Add water to an inch above the level of the beans. Bring them to a boil and then simmer, covered, until tender (about 1 1/2 hours). Mix in the salt, pepper, and paprika. Ladle out 2 cups of the hot bean water and slowly stir it into the flour until smooth. Add the flour mixture to the beans, stirring constantly. Remove the soup from the heat and whisk in the sour cream and then the vinegar. Gently reheat the soup for about 10 minutes.